تمارض در RAVLT: استراتژی بازدارندگی قسمت اول

The effect of warning regarding detection of malingering on the Rey Auditory Verbal Learning Test (RAVLT) was examined in this study. Sixty undergraduate students were randomly assigned to one of four conditions: malingerers, malingerers-with-warnings, warning-only, and control. An incentive that appeared differential, but was an actual constant reward, was offered to participants who could fake in a believable manner (for those in malingering conditions), or to those who performed to the best of their ability (non-malingering conditions). It was predicted that warning participants about the possibility that faking could be detected would modify the behaviour of malingerers, but not those instructed to perform to the best of their ability. Warning had no effect on behaviour in either condition, which was consistent with expectations for the warning-only group, but not for the malingering group. Results are discussed in terms of the ethical and legal issues associated with malingering in neuropsychological practice.

The American Psychiatric Association (1994) defines malingering as intentional production of negative physical or psychological symptoms. Malingering is differentiated from factitious, conversion, and somatoform disorders by the presence of an external incentive. The American Psychiatric Association lists the following examples of external incentives, avoidance of work or military duty, evading criminal prosecution, or the attainment of financial compensation. This definition suggests individuals seeking to avoid undesirable outcomes or gain beneficial outcomes may be motivated to exaggerate or fabricate deficits, including cognitive impairment. Much of the research on malingering in neuropsychology has focussed on methods of detecting malingering (see Haines & Norris, 1995, Nies & Sweet, 1994 and Rogers et al., 1993, for reviews). For example, there have been numerous investigations attempting to determine effective ways of detecting malingering, or seeking to identify the strategies that malingerers use when attempting to avoid detection (e.g., Haines & Norris, 1995). However, there has been much less research on factors that might mediate or reduce malingering behaviour. Of those studies that have explored factors that may reduce malingering behaviour, the main variable of interest has been the effect of warnings on malingering (e.g., Johnson & Lesniak-Karpiak, 1997). The importance of furthering our understanding of this issue is clear, given that in clinical settings neuropsychologists may be ethically obliged to obtain full and informed consent from clients, including acknowledgment that methods of detecting malingering may be employed during assessment (Johnson & Lesniak-Karpiak, 1997). Research in the area of malingering has typically involved the use of volunteers asked to simulate abnormal performance on psychological tests (Nies & Sweet, 1994). However, a number of criticisms have been made of studies using analogue designs that need to be understood in order to evaluate research in this area (e.g., Haines & Norris, 1995). Perhaps most importantly, simulation studies have been criticised for their lack of generalisability Haines & Norris, 1995 and Rogers & Cruise, 1998. This criticism has been attributed to motivational differences between study participants and clients seeking financial reward through litigation, and also because the strategies used in studies investigating malingering may not parallel those used in clinical practice (Bourg, Connor, & Landis, 1995). The American Psychiatric Association's definition of malingering highlights the need to incorporate a motivational element in malingering-simulation research, to replicate external incentives perceived by the clinical population Binder & Pankratz, 1987 and Nies & Sweet, 1994. In recognition of this, Nies and Sweet (1994) have recommended the inclusion of incentives in malingering research. They also recommend informing malingerers of a reward for faking credibly to provide an appropriate model of the clinical situation in which malingering is most likely to occur. Second, malingering-simulation research has been criticised on the grounds that the methods used to induce simulation may not have provided adequate information about symptoms of the group being simulated to ensure realistic faking (Nies & Sweet, 1994). That is, simulation studies require that participants know how to “fake-bad”. However, it should be noted that the extent to which knowledge of symptoms needs to be induced might depend on the type of symptoms being simulated. For example, responses from almost 100 untrained examinees asked to endorse symptoms associated with depression using self-report questionnaires satisfied diagnostic criteria for this illness, compared to 63.3% of the sample endorsing symptoms of mild brain injury and meeting relevant diagnostic criteria (Lees-Haley & Dunn, 1994). This suggests that affective disorders might be easier for naı̈ve subjects to simulate than cognitive deficits. Inducement in malingering studies is usually achieved by coaching participants (showing them how to fake-bad; e.g., Johnson & Lesniak-Karpiak, 1997) or using people with direct knowledge of specific syndromes, such as nurses or psychologists (e.g., Franzen & Martin, 1996 and Hayward et al., 1987). When non-experts are used, some form of coaching of possible cognitive deficits is important as indicated previously, given that lay people have been shown to have little understanding of memory and other cognitive symptoms associated with traumas such as minor head (Aubrey, Dobbs, & Rule, 1989). A variety of methods have been used to coach naı̈ve participants ranging from providing instructions on how to simulate, to the use of vignettes as a means of inducing simulation. As noted previously, when instructions to simulate have been used, these have been criticised as too vague and not providing specific information regarding symptoms (Nies & Sweet, 1994). Similar criticisms have been levelled at the use of simple vignettes (Nies & Sweet, 1994). Failure to provide adequate coaching is a serious issue for malingering-simulation research, as it reduces the likelihood that participants have sufficient knowledge to simulate malingering credibly. In addition, studies that fail to induce credible simulation are at risk of producing results that do not readily generalise to target populations. Clearly, there is a need to devise coaching strategies that induce credible simulation, given that this type of faking is likely to be more difficult to detect, and may more closely reflect the behaviour of malingerers who probably also attempt to educate themselves regarding how to feign deficits or elude detection Berry et al., 1994 and Cochrane et al., 1998.